メッセンジャーRNAキャップ構造の二重機能は,酵母菌におけるポリ (A) -テイル促進トランスレーションにおけるメッセンジャーRNAキャップ構造である
1Gene Expression Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
Nature
|April 21, 1998
まとめ
メッセンジャーRNAのpoly(A) テイルは翻訳プロモーターとして作用し,リボソームを未開封のmRNAに届けます. mRNAキャップ構造と連携して,効率的な翻訳開始と制御を確保します.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- バイオケミストリー バイオケミストリー
背景:
- メッセンジャーRNA (mRNA) の3'ポリアテール尾は,真核生物における翻訳開始と調節に不可欠である.
- これは,mRNA 5'-cap構造のプロモーター活性を増強する翻訳強化剤として概念化されています.
- 尾の長さのポリ (A) 変調は,発達過程で翻訳を調節することが知られている.
研究 の 目的:
- 翻訳開始におけるポリアテールの独立した役割を調査する.
- リボソームのリクルートにおいて,ポリ (A) 尾と5'-キャップ構造の間の相乗効果の相互作用を決定する.
- これらの要素が正確な翻訳の開始と調整をどのように保証するかを明らかにする.
主な方法:
- セルフリートランスレーションアッセイは,Saccharomyces cerevisiae.
- Saccharomyces cerevisiaeにおけるインビボ翻訳分析について.
- カップされたmRNAとカップされていないmRNAを比較した研究で,ポリー (A) 尾の長さは様々である.
主要な成果:
- ポリ (A) 尾は,独立した翻訳プロモーターとして機能し,リボソームを未封鎖のmRNAに提供することができる.
- mRNAがリボソームを争うとき,キャップもポリー・テイルも単独では効率的な翻訳には不十分である.
- カップ構造とポリアテール構造は,リボソームの募集を促進し,mRNA 5'-end.への結合を促進するために連携します.
結論:
- ポリ (A) 尾は,キャップ構造とは独立して,翻訳を開始する際に直接的な役割を果たします.
- ポリ・ア・テイルと5'-キャップ構造の結合作用は,効率的で制御された翻訳開始に不可欠です.
- この機能的相互作用は,翻訳開始コドンの正しい選択と翻訳調節体の適切な作用を保証する.
関連する概念動画
02:01pre-mRNA Processing
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
02:33Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
02:22Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...
02:28Leaky Scanning
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
01:35Pre-mRNA Processing: Modification of pre-mRNA Ends
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
02:22Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...